Earthquakes on August 4, 2021
361
EARTHQUAKES on August 4, 2021
24-hour UTC period · USGS data
LARGEST: M5.8 — 56 km E of Yilan, Taiwan
10 km deep · 30 people felt it
Elevated activitycompared to daily average (~250/day)
Magnitude Breakdown
M5.0+
6
M4.0–4.9
62
M3.0–3.9
15
M2.0–2.9
80
M1.0–1.9
198
Activity Summary
361
Total earthquakes
~250
Daily average
Elevated
Activity level
6
M5.0+ events
Significant Earthquakes (M4.5+)
5.8
56 km E of Yilan, Taiwan
21:50 UTC · 10.0 km deep
Felt by 30
5.5
Nicobar Islands, India region
17:57 UTC · 8.8 km deep
5.5
Vanuatu region
05:55 UTC · 8.0 km deep
5.4
Mid-Indian Ridge
07:17 UTC · 10.0 km deep
5.4
105 km ENE of Hasaki, Japan
04:40 UTC · 14.0 km deep
Felt by 4
5.1
52 km E of Yilan, Taiwan
21:56 UTC · 10.0 km deep
Felt by 1
4.9
222 km SE of Pondaguitan, Philippines
19:11 UTC · 96.6 km deep
4.9
44 km SSW of Sarangani, Philippines
16:56 UTC · 39.0 km deep
Earthquake Map — August 4, 2021
All Earthquakes — August 4, 2021
Showing 30 of 163 (filtered from 361)
(Filtered to M2.0+. Change the magnitude filter to see smaller events.)
| Time ↓ | Mag ↕ | Location ↕ | Depth ↕ | Felt ↕ | MMI | Alert | Status | Details |
|---|---|---|---|---|---|---|---|---|
2021-08-04 2021-08-04 23:31:10 UTC | 4.2mb | 298 km E of Levuka, Fiji -17.884°, -177.868° | 629.6 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021, worldwide seismic activity registered a magnitude 4.2 earthquake 298 km E of Levuka, Fiji at 23:31 UTC. This is the deepest earthquake in the current dataset — a deep-focus event. See the M4.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:28:13 UTC | 4.3mb | 65 km E of Yilan, Taiwan 24.797°, 122.394° | 15.5 km | - | - | - | ✓ Reviewed | USGS → |
At 23:28 UTC on August 4, 2021, a magnitude 4.3 tremor occurred 65 km E of Yilan, Taiwan. Coming 2 hours after a magnitude 5.8 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:26:49 UTC | 2.8ml | 24 km N of Beaver, Alaska 66.577°, -147.446° | 15.0 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021 at 23:26 UTC, a magnitude 2.8 earthquake struck 24 km N of Beaver, Alaska. The event was offshore. See the M2.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:22:53 UTC | 3.1ml | 156 km ESE of Atka, Alaska 51.828°, -171.994° | 35.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 3.1 earthquake 156 km ESE of Atka, Alaska at 23:22 UTC on August 4, 2021. See the M3.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:15:48 UTC | 2.2mh | 7km ESE of Willits, CA 39.393°, -123.276° | 5.1 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.2 seismic event took place 7km ESE of Willits, CA on August 4, 2021 at 23:15 UTC. Coming 1 hours after a magnitude 2.3 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M2.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:12:05 UTC | 3.0md | 29 km SE of Emajagua, Puerto Rico 17.826°, -65.667° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021 at 23:12 UTC, a magnitude 3.0 earthquake struck 29 km SE of Emajagua, Puerto Rico. The event was offshore. See the M3.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 23:05:19 UTC | 2.5ml | 134 km SE of Perryville, Alaska 55.052°, -157.655° | 26.0 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 2.5 event was detected 134 km SE of Perryville, Alaska on August 4, 2021, with origin time 23:05 UTC. The event was offshore. See the M2.5 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 22:38:14 UTC | 2.3md | 3 km NNW of Winlock, Washington 46.521°, -122.961° | -0.3 km | - | - | - | ✓ Reviewed | USGS → |
Reports of a magnitude 2.3 earthquake 3 km NNW of Winlock, Washington came in on August 4, 2021 at 22:38 UTC. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 22:28:57 UTC | 4.4mb | 63 km NW of Lebu, Chile -37.225°, -74.186° | 8.2 km | 1 | - | - | ✓ Reviewed | USGS → |
On August 4, 2021, worldwide seismic activity registered a magnitude 4.4 earthquake 63 km NW of Lebu, Chile at 22:28 UTC. The event was offshore. See the M4.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 22:20:12 UTC | 2.0ml | 55 km ENE of Pedro Bay, Alaska 59.901°, -153.137° | 123.1 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.0 earthquake was recorded 55 km ENE of Pedro Bay, Alaska on August 4, 2021 at 22:20 UTC. See the M2.0 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 22:10:02 UTC | 4.4mb | 76 km SE of Phek, India 25.099°, 94.927° | 99.6 km | - | - | - | ✓ Reviewed | USGS → |
At 22:10 UTC on August 4, 2021, a magnitude 4.4 tremor occurred 76 km SE of Phek, India. The event was offshore. See the M4.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 22:05:44 UTC | 2.3md | 7km ESE of Willits, CA 39.393°, -123.273° | 5.8 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021, worldwide seismic activity registered a magnitude 2.3 earthquake 7km ESE of Willits, CA at 22:05 UTC. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 21:56:27 UTC | 5.1mb | 52 km E of Yilan, Taiwan 24.753°, 122.272° | 10.0 km | 1 | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 5.1 earthquake 52 km E of Yilan, Taiwan at 21:56 UTC on August 4, 2021. Coming 1 hours after a magnitude 5.8 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M5.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 21:53:24 UTC | 4.7mb | 54 km E of Yilan, Taiwan 24.679°, 122.286° | 12.4 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021 at 21:53 UTC, a magnitude 4.7 earthquake struck 54 km E of Yilan, Taiwan. Coming 1 hours after a magnitude 5.8 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. The event was offshore. See the M4.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 21:50:46 UTC | 5.8mww | 56 km E of Yilan, Taiwan 24.783°, 122.311° | 10.0 km | 30 | IV | green | ✓ Reviewed | USGS → |
On August 4, 2021 at 21:50 UTC, a magnitude 5.8 earthquake struck 56 km E of Yilan, Taiwan. In the 72 hours after this event, the USGS recorded 3 smaller earthquakes within 20 km, consistent with an ongoing aftershock sequence rooted here. The USGS PAGER system assigned a green alert level for this event, signalling no significant casualties or damage expected. See the M5.8 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 21:11:39 UTC | 2.4md | 9km W of Petrolia, CA 40.313°, -124.387° | 29.3 km | - | - | - | ✓ Reviewed | USGS → |
Seismographs logged a magnitude 2.4 earthquake 9km W of Petrolia, CA with origin time 21:11 UTC on August 4, 2021. The event was offshore. See the M2.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 20:57:44 UTC | 2.1md | 9 km SE of Magnolia, Arkansas 33.217°, -93.152° | 7.7 km | 2 | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 2.1 earthquake 9 km SE of Magnolia, Arkansas, logged at 20:57 UTC. The event was offshore. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 20:23:40 UTC | 3.1ml | 16 km SE of Waynoka, Oklahoma 36.464°, -98.760° | 8.5 km | 3 | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 3.1 earthquake 16 km SE of Waynoka, Oklahoma, logged at 20:23 UTC. The event was offshore. See the M3.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 20:01:24 UTC | 2.1ml | 43 km NW of Toyah, Texas 31.590°, -104.118° | 8.3 km | - | - | - | ✓ Reviewed | USGS → |
On August 4, 2021 at 20:01 UTC, a magnitude 2.1 earthquake struck 43 km NW of Toyah, Texas. The event was offshore. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:45:15 UTC | 3.2ml | 215 km SE of Perryville, Alaska 54.656°, -156.556° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
At 19:45 UTC on August 4, 2021, a magnitude 3.2 tremor occurred 215 km SE of Perryville, Alaska. The event was offshore. See the M3.2 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:36:05 UTC | 2.9ml | 12km W of Alder Springs, CA 39.670°, -122.859° | 4.3 km | - | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 2.9 earthquake 12km W of Alder Springs, CA, logged at 19:36 UTC. This very shallow event was close enough to the surface that even modest magnitudes can produce significant local shaking. See the M2.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:19:57 UTC | 4.1mb | 14 km SE of Orcopampa, Peru -15.341°, -72.229° | 135.9 km | 1 | - | - | ✓ Reviewed | USGS → |
At 19:19 UTC on August 4, 2021, a magnitude 4.1 tremor occurred 14 km SE of Orcopampa, Peru. The event was offshore. See the M4.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:19:37 UTC | 2.1md | 6 km WSW of La Parguera, Puerto Rico 17.957°, -67.110° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 2.1 earthquake 6 km WSW of La Parguera, Puerto Rico, logged at 19:19 UTC. Coming 16 hours after a magnitude 2.6 earthquake in the immediate vicinity, it is most likely an aftershock of that larger rupture. See the M2.1 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:11:36 UTC | 4.9mb | 222 km SE of Pondaguitan, Philippines 4.857°, 127.517° | 96.6 km | - | - | - | ✓ Reviewed | USGS → |
This magnitude 4.9 event was detected 222 km SE of Pondaguitan, Philippines on August 4, 2021, with origin time 19:11 UTC. The event was offshore. See the M4.9 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:11:11 UTC | 2.3ml | 58 km SSE of Perryville, Alaska 55.412°, -158.853° | 47.0 km | - | - | - | ✓ Reviewed | USGS → |
A magnitude 2.3 seismic event took place 58 km SSE of Perryville, Alaska on August 4, 2021 at 19:11 UTC. See the M2.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 19:03:03 UTC | 3.4ml | 142 km WSW of Adak, Alaska 51.256°, -178.441° | 31.5 km | - | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 3.4 earthquake 142 km WSW of Adak, Alaska, logged at 19:03 UTC. See the M3.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 18:49:46 UTC | 2.7md | 29km SSW of Smith Valley, NV 38.532°, -119.432° | 0.0 km | 3 | - | - | ✓ Reviewed | USGS → |
August 4, 2021 brought a magnitude 2.7 earthquake 29km SSW of Smith Valley, NV, logged at 18:49 UTC. In the 72 hours after this event, the USGS recorded 4 smaller earthquakes within 20 km, consistent with an ongoing aftershock sequence rooted here. See the M2.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 18:34:06 UTC | 4.3mb | 190 km SW of Sungai Penuh, Indonesia -3.305°, 100.209° | 10.0 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 4.3 earthquake 190 km SW of Sungai Penuh, Indonesia at 18:34 UTC on August 4, 2021. The event was offshore. See the M4.3 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 18:29:08 UTC | 4.4mb | 125 km W of Ternate, Indonesia 0.905°, 126.258° | 22.9 km | - | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 4.4 earthquake 125 km W of Ternate, Indonesia at 18:29 UTC on August 4, 2021. The event was offshore. See the M4.4 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
2021-08-04 2021-08-04 18:24:15 UTC | 2.7ml | 36 km NW of Stanley, Idaho 44.483°, -115.215° | 10.0 km | 3 | - | - | ✓ Reviewed | USGS → |
The USGS recorded this magnitude 2.7 earthquake 36 km NW of Stanley, Idaho at 18:24 UTC on August 4, 2021. The event was offshore. See the M2.7 event page for the full report, ShakeMap, and citizen-reported intensity data. | ||||||||
Legend:
Mag: Magnitude (magType = ml, mb, mw, etc.)
Felt: Number of DYFI felt reports
MMI: Modified Mercalli Intensity (I-X+)
Alert: PAGER alert level
Depth: Shallow (<70km), Intermediate, Deep (>300km)
Status: Auto = preliminary, Reviewed = verified by seismologist
Click any row to see additional technical details.
About This Page
This page shows all earthquakes recorded by the USGS Earthquake Hazards Program during the 24-hour UTC period on August 4, 2021. Data includes all events of magnitude 1.0 or greater. Past earthquake data is considered final after review by USGS seismologists.